In the depths of the sea there are many creatures that can inspire terror with their appearance. In many cases, however, these are harmless creatures. Scientists have discovered a new species of deep-sea isopod. It is a crustacean that is kept in an aquarium in Japan. This crustacean was purchased by the Enoshima Aquarium in Fujisawa, Japan, and has only now been discovered to be a new species. The study was published in the Journal of Natural History.

The giant crustacean was already caught in 2017

Deep-sea isopods are large crustaceans that have 14 legs and are found at the greatest depths in the Atlantic, Pacific, and Indian Oceans. A large yellow crustacean was found in a baited trap off Mexico in 2017. It was thought to be a Bathonymus giganteus species. This isopod was described as early as 1879. Thanks to the genetic sequence, it was shown that it is not this species, as it shows more than 35 differences. So the scientists discovered that it is a new and as yet undescribed species of isopod. This new species was named Bathynomus yucatanensis after Mexico’s Yucatán Peninsula, where it was captured over 2,500 feet beneath the waves.

Bathynomus yucatanensis. Body length 260 mm. Credit: Researchers Ming-Chih Huang, Tadashi Kawai & Niel L. Bruce

Interesting creatures

Isopods can immediately impress with their shape, to some they may resemble giant bugs. They are aquatic animals and most of them are no larger than 10 millimeters. The newly discovered species has a length of a respectable 26 centimeters. These are not hunters, but scavengers. When the carcass sinks to the sea floor, these creatures begin to eat the remains.

Bathynomus yucatanensis sp. nov. Holotype (voucher no. TMCD003335). (a) Body, dorsal view; (b) cephalon, anterior view; (c) clypeal region, ventral view; (d) cephalon, lateral view. Scale bars: 1 cm. Credit: Researchers Ming-Chih Huang, Tadashi Kawai & Niel L. Bruce

How are they different?

What is the difference between B. giganteus and the newly discovered B. yucatanensis? The newly discovered species is slimmer, has a shorter body and has longer antennae. It also has a typical yellow shell, while other crustaceans have a gray shell.

Bathynomus giganteus, Credit: Researchers Ming-Chih Huang, Tadashi Kawai & Niel L. Bruce

Scientists assume that the two species shared a common ancestor. There are probably other undiscovered species of Bathynomus in the Gulf of Mexico. It is important to identify new species so that they do not become the target of hunting.

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